A Comparative Karyological and Cytophotometric Study of Normal and Wounded Stem Tissue of the Pea (Pisum sativum L.)

Abstract

The garden pea (Pisum sativum L.) is subject to crown gall tumors. In an attempt to understand the process of initiation of these tumors karyological studies of wounded stem tissue have been made and the results compared with those of karyological and cytophotometric studies of unwounded stem tissue.
Wounding induced increased mitotic activity with polyploid mitoses becoming relatively more frequent. These polyploid cells are more likely to have been present in the tissue at the time of wounding rather than induced by the wounding. Mitoses were found commonly in vascular and pith tissue but not in the cortex. The region of active cell division extended about 500μm from the wound surface. The wound-induced mitotic activity continued for approximately three weeks. The level of mitotic activity and the relative frequency of polyploid mitoses was similar to that found earlier in crown gall tumor tissue, the difference being that the tumor tissue remained mitotically active for approximately three months.